import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: wuqingyu
 * Date: 2022-07-27
 * Time: 10:14
 */
public class TestDemo {
    public static void main(String[] args) {

        //编写程序数一下 1到 100 的所有整数中出现多少个数字9
        int count=0;
        for (int i = 1; i <=100 ; i++) {
            if(i%10==9){
                count++;
            }
            if(i/10==9){
                count++;
            }
        }
        System.out.println(count);
/*

        //打印1-100间的素数
        //产生1-100之间的数
        //素数：只能被1和本身整除
        for (int a = 2; a <=100 ; a++) {
            int flag = 1;
            for (int i = 2; i < a; i++) {
                if(a % i == 0){
                    flag = 0;
                    break;
                }
            }
            if(flag == 1){
                System.out.print(a+" ");
            }
        }
*/



        /*//素数：只能被1和本身整除

        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        int flag = 1;
        if(a<=1){
           flag = 0;
        }else{
           for (int i = 2; i < a; i++) {
               if(a % i == 0){
                   flag = 0;
                   break;
               }
           }
        }
        if(flag == 1){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }*/

        /*int x = 20;
        if (x == 20);else{
            System.out.println("hehe");
        }*/

        /*int y = 2004;
        if(y % 100 != 0){
            if(y % 4 == 0){
                System.out.println(y);
            }

        }else{
            if(y % 400 == 0){
                System.out.println(y);
            }
        }*/
       /* for (int year = 1000; year <=2000 ; year++) {
            if(((year%4==0)&&(year%100!=0))||(year%400==0)){
                System.out.println(year);
            }
        }*/


       /* Scanner scanner = new Scanner(System.in);
        int at = scanner.nextInt();
        System.out.println(-1>>1);
        System.out.println(-1>>>1);*/



        /*System.out.println(10<<1);
        System.out.println(10>>1);
        System.out.println(-10<<1);
        System.out.println(-10>>1);*/

       /* System.out.println(1<<1);//2
        System.out.println(1>>1);//0
        System.out.println(-1<<1);//-2
        System.out.println(-1>>1);//   -1
        System.out.println(0<<1);//0
        System.out.println(0>>1);//0*/

      /*  System.out.println(2<<1);//4
        System.out.println(2>>1);//1
        System.out.println(-2<<1);//-4
        System.out.println(-2>>1);//-1*/
      /*  int a = 5;
        int b = 6;
        System.out.println(a>b & a/0==0);*/
      /*  int a = 5;
        int b = 6;
        //System.out.println(a && b);//error
        System.out.println(a<6 && b>5);//success*/
       /* int a = 10;
        a = ++a;
        System.out.println(a);*/
      /*  int a = 1;
        double d = 12.5;
        //a = (int)(a + d);
        a += d;
        System.out.println(a);*/




        /*System.out.println(10.5%8.5);
        System.out.println(10.5%-8.5);
        System.out.println(-10.5%8.5);
        System.out.println(10%8.5);
        System.out.println(10%8);*/


       /* System.out.println(10%3);//1
        System.out.println(-10%3);//得-3余-1
        System.out.println(10%-3);//得-3余1
        System.out.println(-10%-3);//得3余-1*/

       /* System.out.println(10/0);
        System.out.println(10%0);*/
    }
}
